Telephone cable



Sept. 10, 1935. A. G. SMITH 2,014,214

TELEPHONE CABLE Filed April 9, 1932 2 Sheets-Sheet 1 FIG.

lNVE/VTOR A. 6. SMITH A TTORNEV Sept. 10, 1935. .A. G. SMITH ,2

TELEPHONE CABLE Filed April 9, 1932 2 Sheets-Sheet 2 A TTORNF V Patented Sept. 10, 1935 mural) STATES PATENT OFFICE asslgnor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application April 9, 1932, Serial No. 604,288 In Great Britain May 14, 1931 2 Claims. (01. 173-81) This invention relates to telephone cables and more specifically to the arrangement of conductors in these cables. y

In the design of telephone cables difficulty is 5 sometimes found in arranging a specified number of conductors to form a satisfactory cable core or stranding unit owing to the'generally adopted practice of twisting the conductors together into groups of 2, 4 or 8 conductors (i. e. pairs, quads 0 and similar units, individually screened or nonscreened), before they are stranded to form a cable core. To overcome this difficulty-it has been the practice to include in the cable core additional material, so called "fillers or fill- Alternatively additional conductors of small gauge, either single-that is with earth returnor twisted together in pairs, were used to fill empty spaces in the cable core. When a single invariably used, whereby the quality of the cir cuit was unfavorably affected. In the latter cases the two conductors which compose a circuit, be-

ing twisted together, must necessarily be insertedconductors when the lines joining the centers of the conductors of the same circuits rotate in the same direction along the cable with the same 40 speed, it is necessary that-these center lines he perpendicular to one another.

Thus a stranding unit may comprise a plurality of conductor groups forming pairs, quads,

multiple quads or any other assembly "of pairs, and between some or all of the conductor groups may be situated two. or more single conductor for providing additional circuits.

Figs. 1-12 of the drawings illustratethe manner 50 be applied and Fig. 13 is a simplified drawing of a cross-section ofa telephone cable disclosing the cable structure.

Fig. 1 illustrates schematically the cross-sec-.

tion of a stranding unit comprising two groups I and 2, each consisting 01 a twisted pair, quad,

ings such as paper, jute and similar materials.-

conductor has been inserted, an earth return was inthe main in which the method of the present invention may andten groups I, 2, 3 ...'I0 similar to those .of Fig. 1, the groups being arranged in concentric star or similar structure commonly employed in the construction of telephone cables. Each of the groups may or may not be surrounded by an electrostatic screen. In this figure, a and b, are two separated insulated conductors composing a telephone circuit of specified quality. The structure may or may not be served with a wrapping m of paper or the like.

Fig. 2 illustrates three groups I, 2, 3 similar to those shown in Fig. 1. In this figure, a, b, c, d are four separated conductors forming two and possibly three circuits. The first circuit is composed of a and b, the second of c and d and'the third of a and b in parallel and c and d in parallel. The center lines of the circuits a, b .5 and c, d are perpendicular.

Fig. 3 illustrates a modification of the arrangementshown in Fig. 2. In this case a circuit is composed of a and b and a second of a and b in parallel, and c.

Figs. 4, 5, 6, and 7 illustrate arrangements with four, five, six and seven groups I, 2, 3 I similar to those of Fig. 1. In each case there are four separated conductors a, b, c, d used in the manner described. The condition that the center line of the circuit a, b be'perpendicular to the center line of circuit 0, d is fulfilled in'all cases.

' Figs. it and 9 illustrate arrangements with eight ductors a, b, c, d, e, f, g, h from which four physical and two phantom circuits may be obtained. The condition of freedom from interference between'circuits is fulfilled in all cases.

A telephone cable may contain one or more of any of the structures illustrated in the Figs. 1-12, or structures built upon the same principle in combination with other units of types generally used in the'construction of telephone cables.

Some or all of the conductors in the structures may be loaded in any known manner.

The method described above has particular application to submarine "cables where space is especially valuable.

In Fig. 13 has been shown the structure of a cable built in accordance with the method described above. For the sake of simplicity'only a single layer of quads has been shown. The quads 20 (which are merely representative of any type 0! group structure) are arranged in a single layer within an outer covering 2|. Placed in interstices between these conductor groups 2|) are single conductors 22, 23, 24, and 25 which may or may not be insulated depending on the thickness of the filling between the groups 20 and the size of the conductors 22 to 25, inclusive. Preferably they are made insulated. The center line joining the conductors of circuit l (conductors 22 and 24) is at right angles to the center line of circuit 2 (conductors 23 and 25). In this manner interference between the conductors of circuits l and 2 is reduced to a minimum.

What is claimed is:

1. A communication cable comprising one or more layers of multi-conductor cable units and single conductors inserted in the interstices between contiguous units within the same, layer,

said single conductors being connected so as to form two complete metallic circuits for each layer, the arrangement of said conductors in each layer of said cable being such that a line joining the conductors of one circuit is perpendicular to a line joining the conductors of the other circuit cuits for each layer, the arrangement of said conductors in each layer of said cable being such that a line joining the conductors of one circuit 7 is perpendicular to a line joining the conductors of the other circuit in that layer and such that interference between said circuits is substantially g0 eliminated.

ARTHUR G. SMITH. 

